Lightweight Composites Containing Hemp Hurds

Števulová, Nadežda; Kidalova, Lucia; Cigasova, Julia; Junak, Jozef; Sičáková, Alena; Terpáková, Eva

doi:10.1016/j.proeng.2013.09.013

Cited by 75 publications

(45 citation statements)

References 14 publications

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“…Nevertheless, hemp bio-based materials can have variable mechanical properties in accordance with drying process (Benfratello et al 2013), curing conditions and time of demolding (Pavía et al 2015), nature of the binder matrix (Balčiūnas et al 2013;Dinh 2014;Stevulova et al 2013), composites design (Balčiūnas et al 2013), or hemp shives characteristics (Arnaud and Gourlay 2012;Stevulova et al 2012). Hemp shives characteristics can be length or nature of shives, including with hemp shives in compliance with the requirements of the label hemp aggregate of "Construire en chanvre", meaning "Build with hemp".…”

Section: Introductionmentioning

confidence: 99%

Impact of Bio-Aggregates Properties on the Chemical Interactions with Mineral Binder, Application to Vegetal Concrete

Bourdot

Magniont

Lagouin

et al. 2019

ACT

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Plant concretes were developed and are currently used as filling material in a timber frame. Their properties are strongly related to the bio-aggregates characteristics. In addition, since hemp shiv, the reference bio-based aggregate, has a limited availability, it is necessary to consider alternative bio-aggregates largely and locally available. Thus, this paper focused on identifying and understanding mechanisms of interaction between different bio-aggregates and mineral binders. To address this issue, the first objective was to determine the properties of five hemp shives and two alternative bioaggregates for vegetal lightweight concrete: corn and sunflower bark particles. The study of the chemical interactions between bio-aggregates and a pozzolanic binder was conducted on model pastes mixed with filtered solutions containing bio-aggregates extractives. The mechanical properties of the paste, as well as their hydration and their mineralogical evolution were studied. In the last part, the mechanical behavior of vegetal concretes was assessed. The results highlight a strong relation between the mechanical behavior of pastes and concretes and the extractive content of the different tested bio-aggregates. Finally, pastes appeared as a relatively good model to predict the behavior of concretes by following their early age performances: setting delay and 3-day mechanical strength.

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Section: Introductionmentioning

confidence: 99%

Impact of Bio-Aggregates Properties on the Chemical Interactions with Mineral Binder, Application to Vegetal Concrete

Bourdot

Magniont

Lagouin

et al. 2019

ACT

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“…According to Reference [45], diopside presented a lower degradation rate and increased the mechanical performances. The hemp shiv size can be also taken into consideration for the poor values of the mechanical strength, as References [70,71] showed that, the finer the hemp shiv particles, the stronger the boundaries around the fibers created by the binder will be, and the higher the mechanical characteristics of the composite. The values obtained for the compressive strength are similar to those in Reference [72].…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Experimental Investigations on the Performances of Composite Building Materials Based on Industrial Crops and Volcanic Rocks

2020

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Interdisciplinary and sustainability represent the main characteristics of this paper due to the fact that this research is offering a connection between two main areas-agronomy and construction, by using hemp shiv for the design of new building materials, which can increase the sustainability level of the building industry. For this reason, the main scope of this study is based on the investigation of a new category of composite building materials-lightweight mortars based on hemp shiv, volcanic rocks and white cement-which contribute to a positive environmental impact and help to increase indoor comfort. A complex report was carried out on two segments. The first one is focused upon the characteristics of the raw materials from the composition of the new materials, while the second segment presents a detailed analysis of these composites including morphological and chemical investigation, pyrolytic and fire behavior, compression and flexural strengths, and acoustic and thermal characteristics. The proposed recipes have as a variable volcanic rocks, while the hemp and the binder maintain their volumes and properties. The results were analyzed according to the influence of volcanic rocks on the new composites.Crystals 2020, 10, 102 2 of 21 consideration in the construction sector. There is a significant number of studies on hemp shiv with lime, which is a composite material named hempcrete [12][13][14], but there are only few studies that concern hemp shiv with cement [15][16][17][18][19].Due to the fact that hemp shiv presents poor fire resistance, a new approach can be made with volcanic rocks, which are natural products with higher fire resistance [20]. These materials are usually found in the composition of mortars used in the rehabilitation process of the walls, because of their increased mechanical resistances [21]. They also present sound and thermal properties, as well as a low density, which will help the workability of the mortar. Durable and with higher strength properties for structural application [20], volcanic rocks are low cost materials [22] that also present fire retarding properties for steel structures [23].Therefore, the purpose of this paper is to analyze the impact of the volcanic rocks when these are incorporated in hemp-cement composite materials used as interior mortars. These building materials are developed to be suitable not only for eco-friendly construction but also in regular buildings made from concrete, steel, and so forth, where they can increase indoor comfort. Materials and Methods Raw MaterialsThe composition of the new materials is designed to increase indoor comfort by developing new types of lightweight mortars, obtained as prefabricated plates. In order to understand the characteristics of the new composites, hemp shiv, natural and treated; volcanic rocks, perlite and vermiculite; and binders, white cement and hydrated lime, were analyzed. Hemp ShivThe hemp shiv used for the new composites was received from HempFlax Romania (Pianu De Jos, Alba, Romania). The chemical stru...

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“…The study also included moisture properties such as capillary uptake [15][16][17], water vapor diffusivity [18][19][20][21] and sorption properties [20,21]. Because of the insulating character of the material, the thermal insulation properties (thermal conductivity coefficient) have been tested, depending on the composition of mixtures [13,18,22,23], moisture content [19,24], water content [23], method of compaction [14], compression ratio [25] and hemp shives fraction [22]. According to the literature, the obtained λ values for hemp-lime composites are in the range of 0.074 ÷ 0.138 W/(m•K) [13,15,22].…”

Section: Current Knowledge About Hemp-lime Compositesmentioning

confidence: 99%

The The Occurrence of Thermal Bridges in Hemp-Lime Construction Junctions

Grudzińska

Brzyski

2019

Period. Polytech. Civil Eng.

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Thermal bridges increase heat losses in buildings and reduce the temperature of the internal envelope surface, causing moisture condensation and mould growth. This is an important issue for building materials based on organic components such as a hemp-lime composite, as they are particularly susceptible to biological degradation.The hemp-lime composite is used as a filling in timber frame construction. The increased cross-section of wooden elements together with the geometry change in the construction joints can form thermal bridges. The paper presents numerical analyses of temperature distribution in the area of construction elements connections, taking into account several variants of junctions: external walls, corners, and window placement in a wall. The thermal parameters of hemp-lime composites used in the analyses were obtained from the authors’ own research.Despite relatively good insulating properties, timber elements have a noticeable influence on the local increase of the heat transfer in hemp-lime composite structures, forming thermal bridges in the partitions themselves and in the construction nodes. However, the linear thermal transmittance coefficients in the presented joints were not very significant (in the range of 0.026 ÷ 0.092 W/(m·K) depending on the type of connection), proving the usefulness of this type of construction in energy-efficient buildings.

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Lightweight Composites Containing Hemp Hurds

Cited by 75 publications

References 14 publications

Impact of Bio-Aggregates Properties on the Chemical Interactions with Mineral Binder, Application to Vegetal Concrete

Impact of Bio-Aggregates Properties on the Chemical Interactions with Mineral Binder, Application to Vegetal Concrete

Experimental Investigations on the Performances of Composite Building Materials Based on Industrial Crops and Volcanic Rocks

The The Occurrence of Thermal Bridges in Hemp-Lime Construction Junctions

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